Acetalization of glycerol with acetone over various metal-modified SBA-15 catalysts

Abstract

Several catalysts containing metals such as Al, Zr, Ti and Nb were incorporated in SBA-15 with Si/M ratio = 20 using the hydrothermal process. These catalysts were evaluated for their reactivity during acid-catalyzed condensation of glycerol with acetone to yield a mixture of branched compounds, namely (2,2-dimethyl-[1,3] dioxane-4-yl)-methanol (solketal) and 2,2-dimethyl-[1,3] dioxane-5-ol, which are being used as fuel additives. The synthesised catalyst samples were characterized by ICP-AES analysis, N 2 adsorption-desorption measurements, X-ray diffraction, FT-IR, SEM-EDX, UV-visible diffuse reflectance spectroscopy, TPD of ammonia and ex situ pyridine-adsorbed FT-IR spectroscopy. The various characterization results confirm that metal oxides were incorporated in the pore wall of the SBA-15 matrices. The results of NH 3 -TPD and ex situ adsorbed pyridine FT-IR analyses showed that the acidity of the samples increased after incorporation of metal into the pure SBA-15 samples. Among various metals incorporated into the SBA-15, the Nb-SBA-15 (Si/Nb = 20) showed higher catalytic activity toward the acetalization of glycerol in liquid phase compared to that of other samples investigated. Under the optimal reaction conditions, the Nb-SBA-15 (Si/Nb = 20) exhibited 95% glycerol conversion with 100% solketal selectivity. The catalyst reusability studies indicated that the Nb-SBA-15 sample is regenerable and highly stable in the acetalization of glycerol.

Catalytic Activity and Kinetic Modeling of Various Modules HZMS-5 and Treated MCM-41 Catalysts, for the Liquid-Phase Ketalization of Glycerol With Acetone

“…In addition, reverse, as opposed to forward reaction is faster and therefore water equilibrium does not have any special role. By this reasoning and those suggested in references (Ferreira et al, 2010; Reddy et al, 2011; Royon et al, 2011; Ortiz et al, 2012; Menezes et al, 2013; Nanda et al, 2014b; Aghbashlo et al, 2018, 2019; Ammaji et al, 2018; Fatimah et al, 2019), water equilibrium is not reached nor is it considered necessary for this current proposed kinetic model. Since water is formed during the experimental reaction process, experimentally the effect of water has not been studied in the current work.…”

Glycerol to Solketal for Fuel Additive: Recent Progress in Heterogeneous Catalysts

“…Hydrophobic catalysts, such as hafnium and TUD-1 zirconium on TUD-1, are very prospective for glycerol to solketal. Ammaji et al (2017) [62] also reported a similar observation, as the Zr-SBA-15 was the most active and selective catalyst. Dmitriev et al (2016) [63] reported that zeolite beta was the most active solid acid catalyst as compared to amberlist-35 and cation-exchange resin (KU-2-8) [62].…”

“…Ammaji et al (2017) [62] also reported a similar observation, as the Zr-SBA-15 was the most active and selective catalyst. Dmitriev et al (2016) [63] reported that zeolite beta was the most active solid acid catalyst as compared to amberlist-35 and cation-exchange resin (KU-2-8) [62]. The zeolite beta applied was a commercial one from zeolyst with SiO 2 /Al 2 O 3 of 25 and a zeolite beta made by Angarsk.…”

Process Optimization with Acid Functionalised Activated Carbon derived from Corncob for Production of 4-Hydroxymethyl-2,2-Dimethyl-1,3-Dioxolane and5-Hydroxy-2,2-Dimethyl-1,3-Dioxane

“…The acidic strength of solid acid catalysts in the NH 3 -TPD pro les can be classi ed into three regions depending on their strength in the temperature range. These acidic sites are denoted as weak (150-300 °C), moderate (300-450 °C), and strong (450-650 °C) 12 . The desorption peak of NH 3 -TPDfor AAC-CC shows a weak acidic site at 147.1 °C while showing a sharp peak at 605°C with higher intensity having strong acidic strength ( Figure 11).…”